Australian authorities say they are yet to receive official confirmation from their Chinese counterparts that a pulse had been detected in the search for missing Malaysia Airlines jetliner MH370.

A Chinese patrol ship looking for signs of the aircraft in the southern Indian Ocean recorded a pulse signal with a frequency of 37.5 kHz - matching the signal emitted by flight recorders - on Saturday, China's state news agency Xinhua reported.

A black box detector deployed from the ship Haixun 01 picked up the signal but it hasn’t been established whether it is related to the missing Malaysia Airlines flight MH370, the agency said.

However, Foreign Minister Julie Bishop told the ABC TV’s Insiders on Sunday that the government had yet to receive information from Chinese authorities about the pulse signal.

Ms Bishop said until the report was verified, the information should not be used to raise false hopes for the families of those on board the plane.

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“We have had some evidence of that in the past, so - given that the families are still grieving, that they are very anxious, it is a very distressing time for them - I think we should wait until (retired Air Chief Marshal) Angus Houston confirms one way or another as to whether this is a lead that we can follow,” she said.

Not verified

Earlier, the Australian Maritime Safety Authority (AMSA) said in a statement that reports the Chinese ship, Haixun 01, had detected electronic pulse signals "cannot be verified at this point in time".

As many as 12 planes - 10 of them military ones - and 13 ships will take part in Sunday's search for the missing plane.

Sunday’s search will focus on three separate search areas about 2,000 kilometres north west of Perth, totalling about 216,000 square kilometres, AMSA said in the statement.

Conditions are expected to be favourable, with the cloud base in the search area at about 750 metres above sea level, allowing visibility of more than 10 kilometres.

Signal location

The location of the signal picked up by Chinese ship Haixun 01 is southeast of the official search areas for MH370. It was given as 25 degrees south latitude and 101 degrees east longitude. Photo: Google Earth

Anish Patel, president of pinger manufacturer Dukane Seacom, said both black boxes, for the cockpit voice recorder and the flight data recorder, would emit a standard beacon frequency.

‘‘They’re identical,’’ he said.

The 37.5 kHz signal, which experts say has the same frequency as flight recorders, was reportedly detected at 25 degrees south latitude and 101 degrees east longitude.

A reporter for Chinese state broadcaster CCTV on board the Haixun 01 said rescuers on board the vessel had been searching for a black box signal since Thursday evening.

She said the signal, detected at 4.30pm local time, lasted for one-and-a-half minutes, and while consistent with the frequency standard Boeing jet black boxes would use, that it was "not exclusive" and there was possibility that the signal could be from "other equipment".

The CCTV report confirmed that the Haixun 01 had detected a similar signal on Friday, which lasted 15 minutes, but other ships around may have "disturbed" the signal at the time. The Haixun crew has informed the China rescue coordination centre as well as Australian authorities, according to the report.

A separate report carried on the website of Chinese newspaper Liberation Daily said the signal was first picked up by equipment on the patrol ship on Friday afternoon, and that three team members on the ship confirmed hearing the signal.

The report said the patrol ship picked up the pulse signal again at about 4.30pm on Saturday and were working to confirm whether it could be related to the missing Boeing jet.

Abbott 'hopeful'

Prime Minister Tony Abbott, in Tokyo at the start of a visit to Japan, South Korea and China, said Australia is "hopeful but by no means certain" following the signal pulse detection.

"We need to be very careful about coming to hard and fast conclusions too soon," Mr Abbott said.

Earlier, Air Chief Marshal retired Angus Houston, the head of the search's Joint Agency coordination Centre, said the origins of the electronic pulse signals detected by the Chinese ship could not yet be verified by Australian authorities.

Meanwhile, he revealed that white objects had also been sighted about 90 kilometres from the detection area and Australian authorities were considering sending Royal Australian Air Force assets to the area on Saturday night.

"I have been advised that a series of sounds have been detected by a Chinese ship in the search area. The characteristics reported are consistent with the aircraft black box," Air Chief Marshal (ret) Houston said.

"A number of white objects were also sighted on the surface about 90 kilometres from the detection area. However, there is no confirmation at this stage that the signals and the objects are related to the missing aircraft.

The AMSA and the Australian Transport Safety Bureau have been unable to verify the incidents are linked to the missing flight.

The Australian Rescue Coordination Centre has asked the Chinese Rescue Coordination Centre for "any further information that may be relevant," he said.

"The deployment of RAAF assets to the area where the Chinese ship detected the sounds is being considered."

'Caution' urged

Australian Defence Minister David Johnston urged caution following a number of false leads in what has been an "emotional roller coaster" for those affected by the MH370 tragedy.

"I have not had a chance to get to the bottom of this but can I tell you this is not the first time we've had something that has turned out to be very disappointing," he told ABC24.

"There's a huge chance of false positives here."

Mr Johnston said he would wait to be briefed by Air Chief Marshal (ret) Houston.

While the Defence Minister called for cool heads to prevail, Western Australian oceanographer Charitha Pattiaratchi said the frequency of the signal could ‘‘only come from a human thing".

‘‘If you look at the noise in the ocean and the particular frequencies in there, rain makes a different frequency, whales call at a different frequency. All of the different natural frequencies we know,’’ Professor Pattiaratchi, from the University of Western Australia, said.

‘‘The reason we have the black box at that frequency is so the wave lengths travel pretty fast and it can be picked up. If they've definitely picked up that signal it’s most likely coming from the plane.’’

'Red herrings'

University of Southampton oceanographer, Simon Boxall, said a "variety of things’’ use the same frequency as the pulse signals reportedly detected.

‘‘We've had a lot of red herrings, hyperbole on this whole search," Mr Boxall told CNN. "I'd really like to see this data confirmed...It could be a false signal."

It has been 30 days since the aircraft vanished and there are fears the beacon on the plane’s black boxes might run out of power and stop sending signals.

Although black box beacons have a battery life of about 30 days, they have been known to continue emitting signals for months longer.

Although the search for the missing plane has reached its fourth week, vessels only started searching beneath the ocean's surface in recent days.

The pinger locator can detect a box’s signals, but only from 1.6 kilometres away. The search for wreckage is in 217,000 square kilometres of ocean north-west of Perth.